Nao Saeki

Aono's rival and half-brother. He plays the 1st violin and is a first-year student, born on February 6th. He lived in Germany until he was 12, making him a returnee. Because of this, he struggles with reading and writing in Japanese, which made him stand out in middle school. Even in high school, he needs Aono to add hiragana to kanji during supplementary lessons. Like Aono, he is not good at studying or sports, which is a common trait between the brothers. He started playing the violin at the age of 4 and after returning to Japan, he suddenly achieved excellent results in a competition. He entered Umi Curtain High School through a recommendation exam and joined the orchestra club. He competed in an ensemble with Aono in the club's entrance test and since then, they have been competing with each other in the 1st violin part.

His real mother is a soprano singer who was dating Aono's father. The media caught wind of their affair, which led to a scandal and the downfall of the Aono family. After his grandfather died, he moved to Japan and lived with his maternal grandmother, hoping to meet his half-brother someday. However, when the scandal broke out, he believed that his existence had ruined everything and developed complex feelings of self-denial. He intended to reveal his identity when he first met Aono in high school, but he couldn't bring himself to confess. During the series of events when Aono's mother was hospitalized and fell ill, he finally confessed, and they had a fight where they expressed their true feelings. This allowed them to truly acknowledge each other from the bottom of their hearts.